Circuit-breaker.



No. 800,204. PATENTED SEPT. 26, 1905. O. H. BRIGHAM & J. G. FRANCIS. CIRCUIT BREAKER.

APPLICATION FILED MAR.19,1804.

mm. 711:; z.

UNITED STATES CHARLES H. BRIGHAM, OF NEIV YORK, N. Y., AND JOHN C. FRANCIS, OF

JERSEY; SAID FRANCIS W EEH A W KEN, N EIV BR] GHAM PATENT CFFTCE.

ASSIC-NOR TO SAII) CIRCUIT -BREAKEH.

Specification of Letters Patent.

Eatculcd ."e t. 26, 1905 Application filed March 19,1904. Serial No. 198,981.

To all whom, it may concern.-

Be it known that we, CHARLns H. BRIGHAM, residing at N o. 10 1 est Ninety-fourth street, in the city and State of New York, and JOHN C. FRANCIS, residing at eehawken, in the county of Hudson, in the State of New Jersey, citizens of the United States, have jointly invented a new and useful Improvement in Circuit-Breakers, of which the following is a specification.

Our invention relates to a device for automatically breaking electric circuits which is useful in many connections, and particularly in connection with protectors for telephones and other electrical instruments; and the objects of our invention are to provide a circuit-breaker which is effective, which can be accurately regulated and tested, and which will not be destroyed or even materially impaired by breaking the circuit by means of it. As at present constructed telephone-protectors against sneak-currents, for example, are constructed upon the principle that the circuit may be broken by severing two disks or other points of contact by melting a soldered connection between them or in other ways breaking the circuit by melting a soldered connection. Such protectors require replacing or resoldering after each break of the circuit by means of them, and the protector itself, because of the use of the solder, cannot be accurately regulated or tested. By the use of our invention the protector can be accurately regulated, frequently tested, and after the circuit is broken by means of it and the normal current restored the connection can be made again and the circuit restored without difficulty. e obtain these objects by the device illustrated in the accompanying drawings, in which 7 Figures 1 and 2 are illustrations of the usual telephone protector-frame, showing two sneak-current protectors embodying the principles of our invention. Fig. 3 is an enlarged sectional view of the sneak-current protector embodying the principles of our invention.

Referring to Figs. 1 and 2, 1 and 2 are the line connection, 3 and 4 the switchboard connection, and 5 the grounded connection. 6 and 7 are springs connected and held together by a protector, and 8 and 9 are similar springs connected and held together by a similar protector. This frame thus constructed is substantially the frame now generally used.

Our invention may be readily understood without describing the frame further than to say that when the connection between the springs 6 and 7 is broken the spring? makes the connection with 5 and shunts the current to the ground through 5, and similarly when the connection between the springs 8 and 9 is broken the spring 9 connects with 5 and carries the current to the ground.

Referring to Fig. 3, 10 is a rod provided at one end with a thread and pierced at the other end by a hole .11. 12 is an ordinary nut fitting the thread of the rod. 13 is an insulator insulating the rod from the spring 6. let is a lug to which is fastened the plus end of the wire which carries the current from the spring 6 to the resistancecoil or heat-coil 15. The use of this lug 14 is simply a matter of convenience, enabling the protector to be put in place without the difliculties involved in otherwise making the connection between the resistance-coil or heat-coil 15 and the spring 6. 16 is an insulator in the form of a rubber washer insulating the lug 11 from the lower nut and from the rod 10, to which is aflixed the minus end of the wire of the resistancecoil or heat-coil 15. The resistance-coil or heat-coil 15 is the usual resistance-coil or heatcoil, of German-silver wire or other wire of high resistance, or the same function may be performed by the equivalents of the wire coil, such as carbon or graphite or other matter of high resistance. Curved around the resistance-coil or heat-coil 15 are two pieces of metal of unequal expansion 17 and 18, which are connected together and fastened at one end to the rod 10 and which thus hold'the heat-coil 15 in place. At the other end of the curved pieces of metal 17 and 18 is a pin 19, passing a short distance through the hole 11 in the rod 10. The piece of metal 17, which is inside in relation to the resistancecoil,is preferably of zinc, which readily expands under the influence of heat, and the outside piece of metal 18 is preferably of steel, which is well adapted to hold the pin 19 in its normal position and to return it to its normal position after the excessive current is withdrawn and the normal current restored. The spring 7 is held from the grounded connection by a hook resting on the pin 19, which in turn rests upon the rod 10, thus relieving from any strain the curved pieces of metal 17 and 18. Upon an excess current passing along the spring 6 and thence through the resistance-coil 15 the piece of Zinc 17 expands, drawing the pin 19 back so that the spring 7 is released, breaking the circuit and making the ground connection. 5 After the excess current is withdrawn from the resistance-coil 15 the ZlDC contracts to its original shape and the steel 18 forces back the pin 19 through the hole 11, so that the connection may be readily renewed by simply lift- IO ing the spring 7 so that the hook attached to it engages with the pin 19.

W'hat we claim, and desire to secure by Let ters Patent of the United States, is-

A circuit-breaker comprising two springs, 5 an arm having an eye and supported upon one of the springs, the other spring havinga 

